OMC Manifolds & Risers?

[CharlesW]

The following quote in another thread got my attention.<br />"Also, after 10 years (1994) you are probably WAY OVERDUE for manifolds and risers. Those could have caused your problems."<br />Is 10 years a normal life expectancy of those items on a boat that is used in a freshwater lake only? Having had only two I/O's, this is something I had never heard of before. My first OMC, I owned for 19 years with the original maniflods and risers on a Chevrolet V-8. The second OMC, I have owned since 1993 and it too, still has the original manifolds and risers on a 5.0 Ford. Have I just been lucky or is this maybe not a freshwater problem?<br /><br />Charles

 

[skicat]

Re: OMC Manifolds & Risers?

I too have previously owned OMC's both over ten years old and never heard or thought about needing to change manifolds and risers. What gives?

 

[Boomyal]

Re: OMC Manifolds & Risers?

Ditto here! 29 years and about 1800 hours with small amounts of salt water use.

 

[Ryoken]

Re: OMC Manifolds & Risers?

i deal with saltwater strictly so this info is more a guidline for them. fresh may very well last much longer, i have no experience with them. tho a visual inspection on a real old set would probably be a good idea.<br /><br /> life expectancy is generally 6 to 8 yrs for salt depending on exhaust style. i think merc calls for 6. original setups in salt are lucky to last 10. <br /><br />you can generally get an indicator from the external heat of a riser, either by touch or with a therm gun. this does vary from manufacturer to manufacturer and exhaust styling tho, more of an experience thing. they can also be inspected visually by removing the hose.. <br /><br />risers are not something to mess with, if questionable they should be replaced. i get half a dozen guys a year who lose motors due to them.. one of the most important histories to know on a used boat purchase imo, well, in salt anyway.

 

[yoced]

Re: OMC Manifolds & Risers?

With 'normal' maintenance:<br />Warm salt water (FL) 2-3 years<br />Cold salt water (ME) 3-7 years<br />Warm fresh water (AZ) 6-12 years<br />Cold fresh water (MI) 10-...<br /><br />This is for cast iron raw water cooled manifolds only, and risers will generally fail earlier.